[单选题]ZXUN xAGCF版本升级前,需要检查CGSL操作系统的版本,如果不符合要求,需要进行升级,检查操作系统版本的命令( )。
Before version upgrade of the ZXUN xAGCF, we need to check the version of the CGSL operating system, and we need to upgrade it if it does not comply with requirements. To check the OS version, run the ( ) command. A.cat /etc/klinux-release B.cat /etc/linux-release C.cat /pro/klinux-release D.cat /pro/linux-release